Positive photosensitive resin composition  and cured film forming method using the same

ABSTRACT

There are provided a positive photosensitive resin composition excellent in the sensitivity, film residual ratio and storage stability, comprising a resin containing a specific acrylic acid-based constituent unit capable of dissociating an acid-dissociable group to produce a carboxyl group, the resin being alkali-insoluble or sparingly alkali-soluble and becoming alkali-soluble when the acid-dissociable group dissociates, a resin containing a constituent unit having a functional group capable of reacting with the carboxyl group to form a covalent bond, and a compound capable of generating an acid upon irradiation with an actinic ray or radiation; a cured film forming method using the positive photosensitive resin composition; and a cured film excellent in the heat resistance, adhesion, transmittance and the like.

TECHNICAL FIELD

The present invention relates to a positive photosensitive resincomposition and a cured film forming method using the same. Morespecifically, the present invention relates to a positive photosensitiveresin composition suitable for the formation of a flattening film,protective film or interlayer insulating film of electronic componentssuch as liquid crystal display device, integrated circuit device,solid-state imaging device and organic EL, and a cured film formingmethod using the same.

BACKGROUND ART

Conventionally, in electronic components such as liquid crystal displaydevice, integrated circuit device, solid-state imaging device andorganic EL, a photosensitive resin composition is generally used whenforming a flattening film for imparting flatness to a surface of theelectronic component, a protective film for preventing deterioration ordamage of the electronic component, or an interlayer insulating film forkeeping insulation. For example, in the production of a TFT liquidcrystal display device, a backplate is fabricated by providing apolarizing plate on a glass substrate, forming a transparentelectroconductive circuit layer such as ITO and a thin film transistor(TFT) thereon, and covering the transistor with an interlayer insulatingfilm, a top plate is fabricated by providing a polarizing plate on aglass substrate, forming, if desired, patterns of a black matrix layerand a color filter layer, and further forming sequentially a transparentelectroconductive circuit layer and an interlayer insulating film, andafter disposing these two plates to oppose through a spacer, a liquidcrystal is sealed in between the backplate and the top plate. In thisprocess, the photosensitive resin composition used when forming theinterlayer insulating film is required to be excellent in thesensitivity, residual film ratio, heat resistance, adhesion andtransparency. Also, excellent aging stability during storage is requiredof the photosensitive resin composition.

As regards the photosensitive resin composition, for example, PatentDocument 1 proposes a photosensitive resin composition containing (A) aresin soluble in an aqueous alkali solution, which is a polymer of (a)an unsaturated carboxylic acid or an unsaturated carboxylic anhydride,(b) an epoxy group-containing radical polymerizable compound and (c)another radical polymerizable compound, and (B) a radiation-sensitiveacid-producing compound, and Patent Document 2 proposes a photosensitiveresin composition containing an alkali-soluble acrylic polymer binder, aquinonediazide group-containing compound, a crosslinking agent and aphoto-acid generator. However, both of these compositions areinsufficient in terms of sensitivity, residual film ratio of theunexposed area, resolution and aging stability and are not enough forproducing a high-quality liquid crystal display device. Patent Document3 proposes a positive chemical amplification resist compositioncontaining a crosslinking agent, an acid generator and a resin having aprotective group capable of being cleaved by the action of an acid,where the resin itself is insoluble or sparingly soluble in an aqueousalkali solution but becomes soluble in an aqueous alkali solution aftercleavage of the protective group. However, this composition isinsufficient in terms of adhesion or transmittance and is not enough forproducing a high-quality liquid crystal display device. Patent Document4 proposes a radiation-sensitive resin composition containing an acidgenerator and a resin having an acetal structure and/or a ketalstructure and an epoxy group, but this composition is low in thesensitivity and is not good.

-   Patent Document 1: JP-A-5-165214-   Patent Document 2: JP-A-10-153854-   Patent Document 3: JP-A-2004-4669-   Patent Document 4: JP-A-2004-264623

DISCLOSURE OF THE INVENTION Problems that the Invention is to Solve

Accordingly, an object of the present invention is to provide a positivephotosensitive resin composition excellent in the sensitivity, residualfilm ratio and storage stability, and a cured film forming method usingthe same, which are a positive photosensitive resin composition ensuringthat when cured, a cured film excellent in the heat resistance,adhesion, transmittance and the like is obtained, and a cured filmforming method using the same.

Another object of the present invention is to provide a cured filmobtained using the cured film forming method, and a liquid crystaldisplay device, integrated circuit device, solid-state imaging device ororganic EL device having the cured film.

Means for Solving the Problems

The present inventors have made intensive studies to attain theabove-described objects, as a result, the present invention has beenaccomplished.

The present invention is as follows.

(1) A positive photosensitive resin composition comprising (A1) a resincontaining a constituent unit represented by the following formula (1)having an acid-dissociable group, the resin being alkali-insoluble orsparingly alkali-soluble and becoming alkali-soluble when theacid-dissociable group dissociates, (A2) a resin containing aconstituent unit having a functional group capable of reacting with acarboxyl group to form a covalent bond, and (B) a compound capable ofgenerating an acid upon irradiation with an actinic ray or radiation:

wherein R¹ represents a hydrogen atom, a methyl group, a halogen atom ora cyano group,

each of R² and R³ independently represents a hydrogen atom, a linear orbranched alkyl group, or a cycloalkyl group, provided that at least oneof R² and R³ represents a linear or branched alkyl group or a cycloalkylgroup,

R⁴ represents a linear or branched alkyl group which may be substituted,a cycloalkyl group which may be substituted, or an aralkyl group whichmay be substituted, and

R² or R³ may combine with R⁴ to form a cyclic ether.

(2) The positive photosensitive resin composition as described in (1)above, wherein the component (B) is a compound capable of generating anacid upon irradiation with an actinic ray at a wavelength of 300 nm ormore.

(3) The positive photosensitive resin composition as claimed in claim 1or 2, wherein the component (B) is a compound containing an oximesulfonate group represented by the following formula (2):

wherein R⁵ represents a linear or branched alkyl group which may besubstituted, a cycloalkyl group which may be substituted, or an arylgroup which may be substituted.

(4) The positive photosensitive resin composition as described in anyone of (1) to (3) above, wherein the component (B) is a compoundrepresented by the following formula (3):

wherein R⁵ is the same as R⁵ in formula (2),

X represents a linear or branched alkyl group, an alkoxy group or ahalogen atom,

m represents an integer of 0 to 3, and when m is 2 or 3, each X may bethe same as or different from every other X.

(5) The positive photosensitive resin composition as described in anyone of (1) to (4) above, which further comprises (C) an adhesion aid.

(6) The positive photosensitive resin composition as described in anyone of (1) to (5) above, wherein the component (A2) contains aconstituent unit having a functional group capable of reacting with acarboxyl group to form a covalent bond and a constituent unitrepresented by formula (1).

(7) A cured film forming method comprising a step of applying thepositive photosensitive resin composition described in any one of (1) to(6) above on a substrate and drying it to form a coating film, a step ofexposing the coating film to an actinic ray or radiation through a mask,a step of developing the exposed film with an alkali developer to form apattern, and a step of heat-treating the obtained pattern.

(8) The cured film forming method as described in (7) above, furthercomprising a step of exposing the entire surface of the film, after thestep of developing the coating film with an alkali developer to form apattern but before the step of heat-treating the obtained pattern.

(9) A cured film formed by using the cured film forming method describedin (7) or (8) above.

(10) A liquid crystal display device having the cured film described in(9) above.

(11) An integrated circuit device having the cured film described in (9)above.

(12) A solid-state imaging device having the cured film described in (9)above.

(13) An organic EL device having the cured film described in (9) above.

Furthermore, preferred embodiments of the present invention are setforth below.

(14) The positive photosensitive resin composition as described in anyone of (1) to (6) above, wherein the component (B) is contained in anamount of 0.1 to 10 parts by mass per total 100 parts by mass of thecomponents (A1) and (A2).

(15) The positive photosensitive resin composition as described in anyone of (1) to (6) and (14) above, wherein the component (C) is containedin an amount of 0.1 to 20 parts by mass per total 100 parts by mass ofthe components (A 1) and (A2).

Advantage of the Invention

According to the present invention, there can be provided a positivephotosensitive resin composition excellent in the sensitivity, residualfilm ratio and storage stability and a cured film forming method usingthe same, which are a positive photosensitive resin composition ensuringthat when cured, a cured film excellent in the heat resistance,adhesion, transmittance and the like is obtained, and a cured filmforming method using the same.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is described in detail below.

Incidentally, in the present invention, when a group (atomic group) isdenoted without specifying whether substituted or unsubstituted, thegroup includes both a group having no substituent and a group having asubstituent. For example, an “alkyl group” includes not only an alkylgroup having no substituent (unsubstituted alkyl group) but also analkyl group having a substituent (substituted alkyl group).

The positive photosensitive resin composition of the present inventionis characterized by containing two kinds of specific resins as the resincomponent and a compound capable of generating an acid upon irradiationwith an actinic ray or radiation.

(A) Resin Component

The resin component (A) contained in the positive photosensitive resincomposition of the present invention includes a resin containing aconstituent unit represented by formula (1), the resin beingalkali-insoluble or sparingly alkali-soluble and becoming alkali-solublewhen the acid-dissociable group dissociates (sometimes referred to as a“component (A1)”), and a resin containing a constituent unit having afunctional group capable of reacting with a carboxyl group to form acovalent bond (sometimes referred to as a “component (A2)”), and otherresins may be further contained. The “acid-dissociable group” as usedherein indicates a functional group that can dissociate in the presenceof an acid. Here, the component (A2), that is, the resin containing aconstituent unit having a functional group capable of reacting with acarboxyl group to form a covalent bond, may further contain aconstituent unit containing a constituent unit represented by formula(1), but the resin is regarded as the component (A2).

Component (A1):

The component (A1) is a resin containing a constituent unit representedby formula (1), the resin being alkali-insoluble or sparinglyalkali-soluble and becoming alkali-soluble when the acid-dissociablegroup dissociates.

In formula (1), R¹ represents a hydrogen atom, a methyl group, a halogenatom or a cyano group.

Each of R² and R³ independently represents a hydrogen atom, a linear orbranched alkyl group, or a cycloalkyl group, provided that at least oneof R² and R³ represents an alkyl group or a cycloalkyl group.

R⁴ represents a linear or branched alkyl group which may be substituted,a cycloalkyl group which may be substituted, or an aralkyl group whichmay be substituted.

R² or R³ may combine with R⁴ to form a cyclic ether.

The alkyl group, cycloalkyl group and aralkyl group as R⁴ may have asubstituent, and examples of the substituent include an alkyl group, analkoxy group and a halogen atom. The carbon number of the substituent ispreferably 6 or less.

In formula (1), R¹ is preferably a hydrogen atom or a methyl group.

The alkyl group as R² and R³ is preferably a linear or branched alkylgroup having a carbon number of 1 to 6.

The cycloalkyl group as R² and R³ is preferably a cycloalkyl grouphaving a carbon number of 3 to 6. The alkyl group as R⁴ is preferably alinear or branched alkyl group having a carbon number of 1 to 10.

The cycloalkyl group as R⁴ is preferably a cycloalkyl group having acarbon number of 3 to 10.

The aralkyl group as R⁴ is preferably an aralkyl group having a carbonnumber of 7 to 10.

In the case where R² or R³ combines with R⁴ to form a cyclic ether, itis preferred to form an alkylene chain having a carbon number of 2 to 5by combining R² or R³ with R⁴.

Examples of the radical polymerizable monomer used for forming theconstituent unit represented by formula (1) include a 1-alkoxyalkylacrylate, a 1-alkoxyalkyl methacrylate, a 1-(haloalkoxy)alkyl acrylate,a 1-(haloalkoxy)alkyl methacrylate, a 1-(aralkyloxy)alkyl acrylate, a1-(aralkyloxy)alkyl methacrylate, a tetrahydropyranyl acrylate and atetrahydropyranyl methacrylate. Among these, a 1-alkoxyalkyl acrylate, a1-alkoxyalkyl methacrylate, a tetrahydropyranyl acrylate and atetrahydropyranyl methacrylate are preferred, and a 1-alkoxyalkylacrylate and a 1-alkoxyalkyl methacrylate are more preferred.

Specific examples of the radical polymerizable monomer used for formingthe constituent unit represented by formula (1) include 1-ethoxyethylmethacrylate, 1-ethoxyethyl acrylate, 1-methoxyethyl methacrylate,1-methoxyethyl acrylate, 1-n-butoxyethyl methacrylate, 1-n-butoxyethylacrylate, 1-isobutoxyethyl methacrylate, 1-(2-chloroethoxy)ethylmethacrylate, 1-(2-ethylhexyloxy)ethyl methacrylate, 1-n-propoxyethylmethacrylate, 1-cyclohexyloxyethyl methacrylate,1-(2-cyclohexylethoxy)ethyl methacrylate and 1-benzyloxyethylmethacrylate. One of these monomers may be use alone, or two or morekinds thereof may be used in combination.

The radical polymerizable monomer used for forming the constituent unitrepresented by formula (1) may be a commercially available product ormay be synthesized by a known method. For example, the monomer can besynthesized by reacting a (meth)acrylic acid with a vinyl ether in thepresence of an acid catalyst as shown below.

wherein R¹, R³ and R⁴ correspond to R¹, R³ and R⁴ in formula (1), andR¹³ and R¹⁴ as —CH(R¹³)(R¹⁴) correspond to R² in formula (1).

In the component (A1), a monomer having a constituent unit other thanthe monomer for forming the constituent unit represented by formula (1)may be copolymerized, if desired.

Examples of the constituent unit other than the constituent unitrepresented by formula (1) include constituent units composed ofstyrene, tert-butoxystyrene, methylstyrene, hydroxystyrene,α-methylstyrene, acetoxystyrene, α-methyl-acetoxystyrene,methoxystyrene, ethoxystyrene, chlorostyrene, methyl vinylbenzoate,ethyl vinylbenzoate, acrylic acid, methacrylic acid, methyl acrylate,methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propylacrylate, n-propyl methacrylate, isopropyl acrylate, isopropylmethacrylate, tert-butyl acrylate, tert-butyl methacrylate,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylacrylate, 2-hydroxypropyl methacrylate, benzyl acrylate, benzylmethacrylate, isobornyl acrylate, isobornyl methacrylate, glycidylmethacrylate or acrylonitrile. One of these monomers may be used alone,or two or more kinds thereof may be used in combination.

The content of the constituent unit represented by formula (1) in therepeating unit constituting the component (A1) is preferably from 10 to100 mol %, more preferably from 20 to 90 mol %, still more preferablyfrom 30 to 80 mol %.

The molecular weight of the component (A1) is, as thepolystyrene-equivalent weight average molecular weight, preferably from1,000 to 200,000, more preferably from 2,000 to 50,000.

As for the component (A1), a mixture of two or more kinds of resinscontaining different constituent units may be used, or a mixture of twoor more kinds of resins containing the same constituent unit anddiffering in the composition may be used.

Also, as for the synthesis method of the component (A1), various methodsare known, and, for example, a radical polymerizable monomer mixturecontaining at least a radical polymerizable monomer used for forming theconstituent unit represented by formula (1) is polymerized in an organicsolvent by using a radical polymerization initiator, whereby the resincan be synthesized.

Component (A2):

The component (A2) is a resin containing a constituent unit having afunctional group capable of reacting with a carboxyl group to form acovalent bond.

Examples of the functional group capable of reacting with a carboxylgroup to form a covalent bond include an epoxy group and an oxetanegroup, with an epoxy group being preferred.

The monomer used for synthesizing a resin containing a constituent unithaving a functional group capable of reacting with a carboxyl group toform a covalent bond is preferably a radical polymerizable monomerrepresented by any one of the following formulae (3) to (5). Themolecular weight of the radical polymerizable monomer represented by anyone of formulae (3) to (5) is preferably from 100 to 500, morepreferably from 120 to 200.

In formulae (3) to (5), X represents a divalent linking group, andexamples thereof include —O—, —S— and an organic group such as —COO— and—OCH₂COO—.

R⁷ represents a hydrogen atom, a methyl group or a halogen atom and ispreferably a hydrogen atom or a methyl group.

Each of R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ independently representsa hydrogen atom or an alkyl group and is preferably a hydrogen atom or amethyl group.

n is an integer of 1 to 10.

Specific examples of the radical polymerizable monomer used for formingthe constituent unit containing an epoxy group as the functional groupcapable of reacting with a carboxyl group to form a covalent bondinclude (meth)acrylates such as glycidyl acrylate, glycidylmethacrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate,4,5-epoxypentyl acrylate, 4,5-epoxypentyl methacrylate, 6,7-epoxyheptylacrylate and 6,7-epoxyheptyl methacrylate; vinylbenzyl glycidyl etherssuch as o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether,p-vinylbenzyl glycidyl ether, α-methyl-o-vinylbenzyl glycidyl ether,α-methyl-m-vinylbenzyl glycidyl ether and α-methyl-p-vinylbenzylglycidyl ether; vinylphenyl glycidyl ethers such as o-vinylphenylglycidyl ether, m-vinylphenyl glycidyl ether and p-vinylphenyl glycidylether; 3,4-epoxycyclohexylmethyl acrylate; and 3,4-epoxycyclohexylmethylmethacrylate. Among these monomers, glycidyl acrylate, glycidylmethacrylate, p-vinylphenyl glycidyl ether, 3,4-epoxycyclohexylmethylacrylate and 3,4-epoxycyclohexylmethyl methacrylate are preferred, andglycidyl acrylate and glycidyl methacrylate are more preferred.

Also, a constituent unit having an oxetane group as the functional groupmay be formed using a compound where the epoxy group in those specificexamples of the compound having an epoxy group as the functional groupis replaced by an oxetane group.

The radical polymerizable monomer used for forming the constituent unithaving a functional group capable of reacting with a carboxyl group toform a covalent bond may be a commercially available product or may besynthesized by a known method.

In the component (A2), a monomer having a constituent unit other thanthe radical polymerizable monomer used for forming the constituent unithaving a functional group capable of reacting with a carboxyl group toform a covalent bond may be copolymerized, if desired.

Examples of such a constituent unit include constituent units composedof styrene, tert-butoxystyrene, methylstyrene, hydroxystyrene,α-methylstyrene, acetoxystyrene, α-methyl-acetoxystyrene,methoxystyrene, ethoxystyrene, chlorostyrene, methyl vinylbenzoate,ethyl vinylbenzoate, acrylic acid, methacrylic acid, methyl acrylate,methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propylacrylate, n-propyl methacrylate, isopropyl acrylate, isopropylmethacrylate, tert-butyl acrylate, tert-butyl methacrylate,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylacrylate, 2-hydroxypropyl methacrylate, benzyl acrylate, benzylmethacrylate, isobornyl acrylate, isobornyl methacrylate, glycidylmethacrylate or acrylonitrile. Furthermore, a “monomer capable offorming a constituent unit represented by formula (1)” can becopolymerized.

One of these monomers may be used alone, or two or more kinds thereofmay be used in combination.

In the repeating unit constituting the component (A2), the content ofthe constituent unit having a functional group capable of reacting witha carboxyl group to form a covalent bond is preferably from 10 to 90 mol%, more preferably from 20 to 80 mol %, still more preferably from 30 to70 mol %.

In the repeating unit constituting the component (A2), the content ofthe constituent unit represented by formula (1) is preferably from 0 to70 mol %, more preferably from 5 to 50 mol %.

The molecular weight of the component (A2) is, as thepolystyrene-equivalent weight average molecular weight, preferably from1,000 to 200,000, more preferably from 2,000 to 50,000.

As for the component (A2), a mixture of two or more kinds of resinscontaining different constituent units may be used, or a mixture of twoor more kinds of resins containing the same constituent unit anddiffering in the composition may be used.

Also, as for the synthesis method of the component (A2), various methodsare known, and, for example, a radical polymerizable monomer mixturecontaining at least a radical polymerizable monomer used for forming theconstituent unit having a functional group capable of reacting acarboxyl group to form a covalent bond is polymerized in an organicsolvent by using a radical polymerization initiator, whereby the resincan be synthesized.

The ratio by mass between the component (A1) and the component (A2) ispreferably from 20:80 to 80:20, more preferably from 30:70 to 70:30.

Incidentally, the composition of the present invention may contain aresin other than the component (A1) and the component (A2), and thecontent of the resin other than the component (A1) and the component(A2) is preferably 30 parts by mass or less per total 100 parts by massof the components (A1) and (A2).

In all repeating units of all resins constituting the component (A), thecontent of the constituent unit represented by formula (1) is preferablyfrom 10 to 90 mol %, more preferably from 20 to 50 mol %.

The content of the constituent unit having a functional group capable ofreacting with a carboxyl group to form a covalent bond is preferablyfrom 5 to 50 mol %, more preferably from 10 to 40 mol %.

The content of the constituent unit other than the constituent unitrepresented by formula (1) and the constituent unit having a functionalgroup capable of reacting with a carboxyl group to form a covalent bondis, as a total amount, preferably 85 mol % or less, more preferably 70mol % or less, based on all repeating units of all resins constitutingthe component (A).

(B) Compound Capable of Generating an Acid Upon Irradiation with anActinic Ray or Radiation

Examples of the compound capable of generating an acid upon irradiationwith an actinic ray or radiation (sometimes referred to as a “component(B)”) for use in the present invention include a sulfonium salt, aniodonium salt, a diazomethane compound, an imidosulfonate compound andan oxime sulfonate compound. One of these compounds may be used alone,or two or more kinds thereof may be used in combination.

The component (B) is preferably a compound that is sensitized with anactinic ray at 300 nm or more to generate an acid, more preferably acompound containing an oxime sulfonate group represented by thefollowing formula (2):

In formula (2), R⁵ represents a linear or branched alkyl group which maybe substituted, a cycloalkyl group which may be substituted, or an arylgroup which may be substituted.

R⁵ is preferably a linear or branched alkyl group which may besubstituted, or an aryl group which may be substituted.

The alkyl group of R⁵ is preferably a linear or branched alkyl grouphaving a carbon number of 1 to 10, and the cycloalkyl group ispreferably a cycloalkyl group having a carbon number of 3 to 10.

The alkyl group and cycloalkyl group of R⁵ may be substituted, forexample, by an alkoxy group having a carbon number of 1 to 10 or analicylic group (including a crosslinked alicylic group such as7,7-dimethyl-2-oxonorbornyl group; preferably a bicycloalkyl group orthe like).

The aryl group of R⁵ is preferably an aryl group having a carbon numberof 6 to 11, more preferably a phenyl group or a naphthyl group. The arylgroup of R⁵ may be substituted, for example, by an alkyl group having acarbon number of 1 to 5, an alkoxy group or a halogen atom.

The compound containing an oxime sulfonate group represented by formula(2) is more preferably an oxime sulfonate compound represented by thefollowing formula (3):

In formula (3), R⁵ is the same as R⁵ in formula (2).

X represents a linear or branched alkyl group, an alkoxy group or ahalogen atom.

m represents an integer of 0 to 3, and when m is 2 or 3, each X may bethe same as or different from every other X.

The alkyl group as X is preferably a linear or branched alkyl grouphaving a carbon number of 1 to 4.

The alkoxy group as X is preferably a linear or branched alkoxy grouphaving a carbon number of 1 to 4.

The halogen atom as X is preferably a chlorine atom or a fluorine atom.

m is preferably 0 or 1.

In particular, a compound where in formula (3), m is 1, X is a methylgroup and the substitution position of X is the ortho-position, ispreferred.

Specific examples of the oxime sulfonate compound include the followingcompound (i), compound (ii), compound (iii), compound (iv) and compound(v). One of these compounds may be used alone, or two or more kindsthereof may be used in combination. Also, the compound may be used incombination with another kind of the component (B).

Compounds (i) to (v) are available as a commercial product.

(C) Adhesion Aid

The adhesion aid (C) for use in the present invention is a compound forenhancing adhesion of an insulating film to an inorganic materialworking out to a substrate, for example, a silicon compound such assilicon, silicon oxide and silicon nitride, or a metal such as gold,copper and aluminum. Specific examples thereof include a silane couplingagent and a thiol-based compound.

The silane coupling agent as the adhesion aid for use in the presentinvention is intended to modify the interface and is not particularlylimited, and a known silane coupling agent may be used.

Preferred examples of the silane coupling agent includeγ-glycidoxypropyltrialkoxysilane, γ-glycidoxypropylalkyldialkoxysilane,γ-methacryloxypropyltrialkoxysilane,γ-methacryloxypropylalkyldialkoxysilane, γ-chloropropyltrialkoxysilane,γ-mercaptopropyltrialkoxysilane,β-(3,4-epoxycyclohexyl)ethyltrialkoxysilane and vinyltrialkoxysilane.

Among these, γ-glycidoxypropyltrialkoxysilane andγ-methacryloxypropyltrialkoxysilane are more preferred, andγ-glycidoxypropyltrialkoxysilane is still more preferred.

One of these silane coupling agents may be used alone, or two or morekinds thereof may be used in combination. These are effective not onlyfor enhancing the adhesion to a substrate but also for adjusting thetaper angle with the substrate.

In the positive photosensitive resin composition of the presentinvention, as for the mixing ratio of the component (A), component (B)and component (C), the ratio of the component (B) is preferably from 0.1to 10 parts by mass, more preferably from 0.5 to 5 parts by mass, andthe ratio of the component (C) is preferably from 0.1 to 20 parts bymass, more preferably from 0.5 to 10 parts by mass, per total 100 partsby mass of the components (A1) and (A2)

<Other Components>

In the positive photosensitive resin composition of the presentinvention, in addition to the component (A), component (B) and component(C), a basic compound, a surfactant, an ultraviolet absorber, asensitizer, a plasticizer, a thickener, an organic solvent, an organicor inorganic precipitation inhibitor, and the like may be added, ifdesired.

<Basic Compound>

The basic compound which can be used may be arbitrarily selected fromthose used in chemical amplification resists. Examples thereof includean aliphatic amine, an aromatic amine, a heterocyclic amine, aquaternary ammonium hydroxide and a quaternary ammonium carboxylate.

Examples of the aliphatic amine include trimethylamine, diethylamine,triethylamine, di-n-propylamine, tri-n-propylamine, di-n-pentylamine,tri-n-pentylamine, diethanolamine, triethanolamine, dicyclohexylamineand dicyclohexylmethylamine.

Examples of the aromatic amine include aniline, benzylamine,N,N-dimethylaniline and diphenylamine.

Examples of the heterocyclic amine include pyridine, 2-methylpyridine,4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine,4-phenylpyridine, N-methyl-4-phenylpyridine, 4-dimethylaminopyridine,imidazole, benzimidazole, 4-methylimidazole, 2-phenylbenzimidazole,2,4,5-triphenylimidazole, nicotine, nicotinic acid, nicotinamide,quinoline, 8-oxyquinoline, pyrazine, pyrazole, pyridazine, purine,pyrrolidine, piperidine, piperazine, morpholine, 4-methylmorpholine,1,5-diazabicyclo[4,3,0]-5-nonene and 1,8-diazabicyclo[5,3,0]-7-undecene.

Examples of the quaternary ammonium hydroxide includetetramethylammonium hydroxide, tetraethylammonium hydroxide,tetra-n-butylammonium hydroxide and tetra-n-hexylammonium hydroxide.

Examples of the quaternary ammonium carboxylate includetetramethylammonium acetate, tetramethylammonium benzoate,tetra-n-butylammonium acetate and tetra-n-butylammonium benzoate.

The amount of the basic compound blended is preferably from 0.001 to 1part by mass, more preferably from 0.005 to 0.2 parts by mass, per total100 parts by mass of the components (A1) and (A2).

<Surfactant>

As for the surfactant, any of an anionic surfactant, a cationicsurfactant, a nonionic surfactant and an amphoteric surfactant may beused, but the preferred surfactant is a nonionic surfactant. Examples ofthe nonionic surfactant which can be used include polyoxyethylene higheralkyl ethers, polyoxyethylene higher alkyl phenyl ethers, higher fattyacid diesters of polyethylene glycol, and silicon-containing orfluorine-containing surfactants. Also, the nonionic surfactant includesrespective series of, as trade names, KP (produced by Shin-Etsu ChemicalCo., Ltd.), Polyflow (produced by Kyoeisha Chemical Co., Ltd.), EFtop(produced by JEMCO), Megaface (produced by Dainippon Ink and Chemicals,Inc.), Florad (produced by Sumitomo 3M, Ltd.), Asahi Guard, Surflon(produced by Asahi Glass Co., Ltd.) and PolyFox (produced by OMNOVA).

One surfactant may be used alone, or two or more kinds of surfactantsmay be mixed and used.

The amount of the surfactant blended is usually 10 parts by mass orless, preferably from 0.01 to 10 parts by mass, more preferably from0.01 to 1 part by mass, per total 100 parts by mass of the components(A1) and (A2).

<Plasticizer>

Examples of the plasticizer include dibutyl phthalate, dioctylphthalate, didodecyl phthalate, polyethylene glycol, glycerin, dimethylglycerin phthalate, dibutyl tartrate, dioctyl adipate and triacetylglycerin.

The amount of the plasticizer blended is preferably from 0.1 to 30 partsby mass, more preferably from 1 to 10 parts by mass, per total 100 partsby mass of the components (A1) and (A2).

<Solvent>

The positive photosensitive composition of the present invention is usedas a solution by dissolving the above-described components in a solvent.Examples of the solvent used for the positive photosensitive compositionof the present invention include:

(a) ethylene glycol monoalkyl ethers such as ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethylene glycol monopropyl etherand ethylene glycol monobutyl ether;

(b) ethylene glycol dialkyl ethers such as ethylene glycol dimethylether, ethylene glycol diethyl ether and ethylene glycol dipropyl ether;

(c) ethylene glycol monoalkyl ether acetates such as ethylene glycolmonomethyl ether acetate, ethylene glycol monoethyl ether acetate,ethylene glycol monopropyl ether acetate and ethylene glycol monobutylether acetate;

(d) propylene glycol monoalkyl ethers such as propylene glycolmonomethyl ether, propylene glycol monoethyl ether, propylene glycolmonopropyl ether and propylene glycol monobutyl ether;

(e) propylene glycol dialkyl ethers such as propylene glycol dimethylether and propylene glycol diethyl ether;

(f) propylene glycol monoalkyl ether acetates such as propylene glycolmonomethyl ether acetate, propylene glycol monoethyl ether acetate,propylene glycol monopropyl ether acetate and propylene glycol monobutylether acetate;

(g) diethylene glycol monoalkyl ethers such as diethylene glycolmonomethyl ether and diethylene glycol monoethyl ether;

(h) diethylene glycol dialkyl ethers such as diethylene glycol dimethylether, diethylene glycol diethyl ether and diethylene glycol ethylmethyl ether;

(i) diethylene glycol monoalkyl ether acetates such as diethylene glycolmonomethyl ether acetate, diethylene glycol monoethyl ether acetate,diethylene glycol monopropyl ether acetate and diethylene glycolmonobutyl ether acetate;

(j) dipropylene glycol monoalkyl ethers such as dipropylene glycolmonomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycolmonopropyl ether and dipropylene glycol monobutyl ether;

(k) dipropylene glycol dialkyl ethers such as dipropylene glycoldimethyl ether, dipropylene glycol diethyl ether and dipropylene glycolethyl methyl ether;

(l) dipropylene glycol monoalkyl ether acetates such as dipropyleneglycol monomethyl ether acetate, dipropylene glycol monoethyl etheracetate, dipropylene glycol monopropyl ether acetate and dipropyleneglycol monobutyl ether acetate;

(m) lactic acid esters such as methyl lactate, ethyl lactate, n-propyllactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, n-amyllactate and isoamyl lactate;

(n) aliphatic carboxylic acid esters such as n-butyl acetate, isobutylacetate, n-amyl acetate, isoamyl acetate, n-hexyl acetate, 2-ethylhexylacetate, ethyl propionate, n-propyl propionate, isopropyl propionate,n-butyl propionate, isobutyl propionate, methyl butyrate, ethylbutyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butylbutyrate and isobutyl butyrate;

(o) other esters such as ethyl hydroxyacetate, ethyl2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-3-methylbutyrate, ethylmethoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl3-methoxypropionate, methyl 3-ethoxypropionate, ethyl3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutylacetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutylbutyrate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate andethyl pyruvate;

(p) ketones such as methyl ethyl ketone, methyl propyl ketone, methyln-butyl ketone, methyl isobutyl ketone, 2-heptanone, 3-heptanone,4-heptanone and cyclohexanone;

(q) amides such as N-methylformamide, N,N-dimethylformamide,N-methylacetamide, N,N-dimethylacetamide and N-methylpyrrolidone; and

(r) lactones such as γ-butyrolactone.

Also, a solvent such as benzyl ethyl ether, dihexyl ether, ethyleneglycol monophenyl ether acetate, diethylene glycol monomethyl ether,diethylene glycol monoethyl ether, isophorone, caproic acid, caprylicacid, 1-octanol, 1-nonal, benzyl alcohol, anisole, benzyl acetate, ethylbenzoate, diethyl oxalate, diethyl maleate, ethylene carbonate andpropylene carbonate may be further added, if desired, to the solventabove.

One solvent may be used alone, or two or more kinds of solvents may bemixed and used.

The amount of the solvent blended is usually from 50 to 3,000 parts bymass, preferably from 100 to 2,000 parts by mass, more preferably from100 to 500 parts by mass, per total 100 parts by mass of the components(A1) and (A2).

By virtue of using the positive photosensitive resin compositioncontaining the components (A) and (B), a positive photosensitive resincomposition excellent in the sensitivity, residual film ratio and agingstability can be provided, which is a positive photosensitive resincomposition ensuring that when cured, a cured film excellent in the heatresistance, adhesion, transparency and the like is obtained.

<Cured Film Forming Method>

The cured film forming method using the positive photosensitive resincomposition of the present invention is described below.

The positive photosensitive resin composition of the present inventionis applied on a substrate and dried by heating to form a coating film onthe substrate.

The obtained coating film is irradiated with an actinic ray orradiation, whereby the component (B) decomposes and an acid isgenerated. By the catalytic action of the acid generated, theacid-dissociable group in the constituent unit represented by formula(1) contained in the component (A1) dissociates through a hydrolysisreaction, and a carboxyl group is produced. The exposed coating film isdeveloped by using an alkali developer, and the exposed area containinga carboxyl group-containing resin easy to dissolve in an alkalideveloper is thereby removed, as a result, a positive image is formed.

The reaction formula of the hydrolysis reaction is shown below.

In order to accelerate the hydrolysis reaction, post exposure baking(hereinafter referred to as “PEB”) may be performed, if desired. Here,if the heating temperature is high, the carboxyl group generated causesa crosslinking reaction with the constituent unit having a functionalgroup capable of reacting with a carboxyl group to form a covalent bond,and it becomes impossible to effect development.

Actually, when tert-butyl methacrylate is used in place of the repeatingunit represented by formula (1), because of high activation energy ofthe acid dissociation reaction, PEB must be performed at a hightemperature to dissociate the acid-dissociable group, but a crosslinkingreaction occurs at the same time and an image cannot be obtained.

On the other hand, the acid-dissociable group represented by formula (1)of the present invention is low in the activation energy of aciddecomposition and produces a carboxyl group by readily decomposing inthe presence of an acid derived from an acid generator upon exposure andtherefore, PEB need not be performed, so that a positive image can beformed by development.

Incidentally, decomposition of the acid-dissociable group may beaccelerated by performing PEB at a relatively low temperature withoutcausing a crosslinking reaction.

The PEB temperature is preferably 130° C. or less, more preferably 110°C. or less, still more preferably 80° C. or less.

The obtained positive image is then heated, as a result, theacid-dissociable group in formula (1) thermally decomposes to produce acarboxyl group, and the carboxyl group is crosslinked with a structureto be crosslinked, whereby a cured film can be formed. This heating ispreferably performed at a high temperature of 150° C. or more, morepreferably at 180 to 250° C., still more preferably at 200 to 250° C.

The heating time may be appropriately set according to the heatingtemperature and the like but is generally from 10 to 90 minutes. When astep of irradiating the entire surface with an actinic ray or radiationis added before the heating step, the crosslinking reaction can beaccelerated by an acid generated upon irradiation with an actinic ray orradiation.

The cured film forming method using the positive photosensitive resincomposition of the present invention is specifically described below.

Preparation Method of Composition Solution:

The components (A) and (B) and other components to be blended are mixedin a predetermined ratio by an arbitrary method and dissolved withstirring to prepare a composition solution. The composition solution canalso be prepared, for example, by previously dissolving each componentin a solvent to obtain a solution and mixing these solutions in apredetermined ratio. The composition solution prepared in this way maybe filtered using a filter or the like having a pore size of 0.2 μm andthen used.

<Coating Film Forming Method>

The composition solution is applied on a predetermined substrate, andthe solvent is removed by heating (hereinafter referred to as“pre-baking”), whereby a desired coating film can be formed. Forexample, in the production of a liquid crystal display device, examplesof the substrate include a glass plate having provided thereon apolarizing plate, where a black matrix layer and a color filter layerare further provided, if desired, and a transparent electroconductivecircuit layer is further provided thereon. The applying method on thesubstrate is not particularly limited and, for example, a method such asspraying method, roll coating method, spin coating method and slitcoating method may be used.

Also, the heating conditions at the pre-baking are set such that in theunexposed area, an acid-dissociable group, for example, in the repeatingunit represented by formula (1) in the component (A) is not allowed todissociate and make the component (A) soluble in an alkali developer,and although the conditions vary depending on the kind and blendingratio of respective components, the heating is preferably performedapproximately at 80 to 130° C. for 30 to 120 seconds.

<Pattern Forming Method>

The substrate having provided thereon the coating film is irradiatedwith an actinic ray or radiation through a mask having a predeterminedpattern and after performing, if desired, a heat treatment (PEB), theexposed area is removed by using a developer to form an image pattern.

For the irradiation of an actinic ray or radiation, a low-pressuremercury lamp, a high-pressure mercury lamp, an ultrahigh-pressuremercury lamp, a chemical lamp, an excimer laser generator or the likemay be used, but an actinic ray at a wavelength of 300 nm or more, suchas g-line, i-line and h-line, is preferred. Also, if desired, theirradiation light may be adjusted through a spectral filter such as longwavelength cut filter, short wavelength cut filter and band pass filter.

Examples of the developer which can be used include aqueous solutionsof: alkali metal hydroxides such as lithium hydroxide, sodium hydroxideand potassium hydroxide; alkali metal carbonates such as sodiumcarbonate and potassium carbonate; alkali metal bicarbonates such assodium bicarbonate and potassium bicarbonate; ammonium hydroxides suchas tetramethylammonium hydroxide, tetraethylammonium hydroxide andcholine hydroxide; sodium silicate; or sodium metasilicate. Also, anaqueous solution obtained by adding a water-soluble organic solvent suchas methanol or ethanol and a surfactant in appropriate amounts to theabove-described aqueous solution of alkalis may be used as thedeveloper.

The pH of the developer is preferably from 10.0 to 14.0.

The development time is preferably from 30 to 180 seconds, and thedevelopment method may be any of puddling, dipping and the like. Afterthe development, washing with running water is performed for 30 to 90seconds, whereby a desired pattern can be formed.

<Crosslinking Step>

The pattern with unexposed area obtained by development is heat-treatedusing a heating device such as hot plate or oven at a predeterminedtemperature, for example, at 180 to 250° C., for a predetermined time,for example, for 5 to 30 minutes on a hot plate or for 30 to 90 minutesin an oven, as a result, the acid-dissociable group in the component(A1) dissociates to generate a carboxyl group and the carboxyl group isallowed to react and crosslink with a structure in the component (A2)capable of crosslinking with a carboxyl group, whereby a protective filmor interlayer insulating film excellent in the heat resistance, hardnessand the like can be formed. Also, the transparency can be enhanced byperforming the heat treatment in a nitrogen atmosphere.

Incidentally, in advance of the heat treatment, the substrate afterpattern formation is preferably irradiated with an actinic ray orradiation to generate an acid from the component (B) present in theunexposed portion.

EXAMPLES

The present invention is described in greater detail below by referringto Examples, but the present invention is not limited to these Examples.

Synthesis Example 1 Synthesis of A1-1

Into a 500 ml-volume three-neck flask, 67.1 g (0.36 mol) of1-n-butoxyethyl methacrylate, 21.1 g (0.12 mol) of benzyl methacrylate,10.3 g (0.12 mol) of methacrylic acid and 300 ml of methyl isobutylketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in propylene glycolmonomethyl ether acetate, and heptane and methyl isobutyl ketonecontained in the solution were removed by distillation under reducedpressure to obtain Polymer A1-1 (1-n-butoxyethyl methacrylate/benzylmethacrylate/methacrylic acid) as a propylene glycol monomethyl etheracetate solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 8,000 andthe molecular weight distribution (Mw/Mn) was 1.8.

Synthesis Example 2 Synthesis of A1-2

Into a 500 ml-volume three-neck flask, 105.7 g (0.48 mol) of1-benzyloxyethyl methacrylate, 7.8 g (0.06 mol) of 2-hydroxyethylmethacrylate, 5.2 g (0.06 mol) of methacrylic acid and 300 ml of methylisobutyl ketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in diethylene glycoldimethyl ether, and heptane and methyl isobutyl ketone contained in thesolution were removed by distillation under reduced pressure to obtainPolymer A1-2 (1-benzyloxyethyl methacrylate/2-hydroxyethylmethacrylate/methacrylic acid) as a diethylene glycol dimethyl ethersolution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 4,000 andthe molecular weight distribution (Mw/Mn) was 1.6.

Synthesis Example 3 Synthesis of A1-3

Into a 500 ml-volume three-neck flask, 66.4 g (0.42 mol) of1-ethoxyethyl methacrylate, 21.1 g (0.12 mol) of benzyl methacrylate,7.8 g (0.06 mol) of 2-hydroxyethyl methacrylate and 300 ml of methylisobutyl ketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in diethylene glycolethyl methyl ether, and heptane and methyl isobutyl ketone contained inthe solution were removed by distillation under reduced pressure toobtain Polymer A1-3 (1-ethoxyethyl methacrylate/benzylmethacrylate/2-hydroxyethyl methacrylate) as a diethylene glycol ethylmethyl ether solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 4,000 andthe molecular weight distribution (Mw/Mn) was 1.6.

Synthesis Example 4 Synthesis of A1-4

Into a 500 ml-volume three-neck flask, 51.9 g (0.36 mol) of1-ethoxyethyl acrylate, 31.7 g (0.18 mol) of benzyl methacrylate, 7.8 g(0.06 mol) of 2-hydroxyethyl methacrylate and 300 ml of methyl isobutylketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in propylene glycolmonomethyl ether acetate, and heptane and methyl isobutyl ketonecontained in the solution were removed by distillation under reducedpressure to obtain Polymer A1-4 (1-ethoxyethyl acrylate/benzylmethacrylate/2-hydroxyethyl methacrylate) as a propylene glycolmonomethyl ether acetate solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 5,000 andthe molecular weight distribution (Mw/Mn) was 1.7.

Synthesis Example 5 Synthesis of A1-5

Into a 500 ml-volume three-neck flask, 28.5 g (0.18 mol) of1-ethoxyethyl methacrylate, 52.9 g (0.30 mol) of benzyl methacrylate,10.3 g (0.12 mol) of methacrylic acid and 300 ml of methyl isobutylketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in diethylene glycoldimethyl ether, and heptane and methyl isobutyl ketone contained in thesolution were removed by distillation under reduced pressure to obtainPolymer A1-5 (1-ethoxyethyl methacrylate/benzyl methacrylate/methacrylicacid) as a diethylene glycol dimethyl ether solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 12,000 andthe molecular weight distribution (Mw/Mn) was 1.8.

Synthesis Example 6 Synthesis of A1-6

Into a 500 ml-volume three-neck flask, 63.7 g (0.30 mol) of1-cyclohexyloxyethyl methacrylate, 40.3 g (0.30 mol) of p-methoxystyreneand 300 ml of methyl isobutyl ketone were charged. A catalytic amount of2,2′-azobis(methyl 2-methylpropionate) was added thereto as a radicalpolymerization initiator, and polymerization was allowed to proceed at80° C. for 6 hours in a nitrogen stream. The reaction solution wascooled and then poured in a large amount of heptane to precipitate apolymer. The crystal was collected by filtration and dissolved indiethylene glycol ethyl methyl ether, and heptane and methyl isobutylketone contained in the solution were removed by distillation underreduced pressure to obtain Polymer A1-6 (1-cyclohexyloxyethylmethacrylate/p-methoxystyrene) as a diethylene glycol ethyl methyl ethersolution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 8,000 andthe molecular weight distribution (Mw/Mn) was 1.7.

Synthesis Example 7 Synthesis of A1-7

Into a 500 ml-volume three-neck flask, 71.5 g (0.42 mol) of2-tetrahydropyranyl methacrylate, 19.5 g (0.12 mol) of p-acetoxystyrene,7.8 g (0.06 mol) of 2-hydroxyethyl methacrylate and 300 ml of methylisobutyl ketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in a mixed solvent ofpropylene glycol monomethyl ether acetate and diethylene glycol ethylmethyl ether, and heptane and methyl isobutyl ketone contained in thesolution were removed by distillation under reduced pressure to obtainPolymer A1-7 (2-tetrahydropyranylmethacrylate/p-acetoxystyrene/2-hydroxyethyl methacrylate) as a solutionin a mixed solvent of propylene glycol monomethyl ether acetate anddiethylene glycol ethyl methyl ether.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 6,000 andthe molecular weight distribution (Mw/Mn) was 1.7.

Synthesis Example 8 Synthesis of A2-1

Into a 500 ml-volume three-neck flask, 51.2 g (0.36 mol) of glycidylmethacrylate, 42.3 g (0.24 mol) of benzyl methacrylate and 300 ml ofmethyl isobutyl ketone were charged. A catalytic amount of2,2′-azobis(methyl 2-methylpropionate) was added thereto as a radicalpolymerization initiator, and polymerization was allowed to proceed at80° C. for 6 hours in a nitrogen stream. The reaction solution wascooled and then poured in a large amount of heptane to precipitate apolymer. The crystal was collected by filtration and dissolved indiethylene glycol dimethyl ether, and heptane and methyl isobutyl ketonecontained in the solution were removed by distillation under reducedpressure to obtain Polymer A2-1 (glycidyl methacrylate/benzylmethacrylate) as a diethylene glycol dimethyl ether solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 8,000 andthe molecular weight distribution (Mw/Mn) was 1.7.

Synthesis Example 9 Synthesis of A2-2

Into a 500 ml-volume three-neck flask, 46.1 g (0.36 mol) of glycidylacrylate, 15.6 g (0.12 mol) of 2-hydroxyethyl methacrylate, 19.5 g (0.12mol) of p-acetoxystyrene and 300 ml of methyl isobutyl ketone werecharged. A catalytic amount of 2,2′-azobis(methyl 2-methylpropionate)was added thereto as a radical polymerization initiator, andpolymerization was allowed to proceed at 80° C. for 6 hours in anitrogen stream. The reaction solution was cooled and then poured in alarge amount of heptane to precipitate a polymer. The crystal wascollected by filtration and dissolved in diethylene glycol dimethylether, and heptane and methyl isobutyl ketone contained in the solutionwere removed by distillation under reduced pressure to obtain PolymerA2-2 (glycidyl acrylate/2-hydroxyethyl methacrylate/p-acetoxystyrene) asa diethylene glycol dimethyl ether solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 5,000 andthe molecular weight distribution (Mw/Mn) was 1.6.

Synthesis Example 10 Synthesis of A2-3

Into a 500 ml-volume three-neck flask, 58.9 g (0.30 mol) of3,4-epoxycyclohexylmethyl methacrylate (Cyclomer M100, produced byDaicel Chemical Industries, Ltd.), 31.7 g (0.18 mol) of benzylmethacrylate, 10.3 g (0.12 mol) of methacrylic acid and 300 ml of methylisobutyl ketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in diethylene glycoldimethyl ether, and heptane and methyl isobutyl ketone contained in thesolution were removed by distillation under reduced pressure to obtainPolymer A2-3 (3,4-epoxycyclohexylmethyl methacrylate/benzylmethacrylate/methacrylic acid) as a diethylene glycol dimethyl ethersolution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 7,000 andthe molecular weight distribution (Mw/Mn) was 1.7.

Synthesis Example 11 Synthesis of A2-4

Into a 500 ml-volume three-neck flask, 52.9 g (0.30 mol) ofp-vinylphenyl glycidyl ether, 19.0 g (0.12 mol) of 1-ethoxyethylmethacrylate, 29.2 g (0.18 mol) of p-acetoxystyrene and 300 ml of methylisobutyl ketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in diethylene glycoldimethyl ether, and heptane and methyl isobutyl ketone contained in thesolution were removed by distillation under reduced pressure to obtainPolymer A2-4 (p-vinylphenyl glycidyl ether/1-ethoxyethylmethacrylate/p-acetoxystyrene) as a diethylene glycol dimethyl ethersolution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 4,000 andthe molecular weight distribution (Mw/Mn) was 1.6.

Synthesis Example 12 Synthesis of A2-5

Into a 500 ml-volume three-neck flask, 34.1 g (0.24 mol) of glycidylmethacrylate, 38.0 g (0.24 mol) of 1-ethoxyethyl methacrylate, 15.6 g(0.12 mol) of 2-hydroxyethyl methacrylate and 300 ml of methyl isobutylketone were charged. A catalytic amount of 2,2′-azobis(methyl2-methylpropionate) was added thereto as a radical polymerizationinitiator, and polymerization was allowed to proceed at 80° C. for 6hours in a nitrogen stream. The reaction solution was cooled and thenpoured in a large amount of heptane to precipitate a polymer. Thecrystal was collected by filtration and dissolved in diethylene glycoldimethyl ether, and heptane and methyl isobutyl ketone contained in thesolution were removed by distillation under reduced pressure to obtainPolymer A2-5 (glycidyl methacrylate/1-ethoxyethylmethacrylate/2-hydroxyethyl methacrylate) as a diethylene glycoldimethyl ether solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 9,000 andthe molecular weight distribution (Mw/Mn) was 1.7.

Synthesis Example 13 Synthesis of A2-6

Into a 500 ml-volume three-neck flask, 34.1 g (0.24 mol) of glycidylmethacrylate, 28.5 g (0.18 mol) of 1-ethoxyethyl methacrylate, 7.8 g(0.06 mol) of 2-hydroxyethyl methacrylate, 21.1 g (0.12 mol) of benzylmethacrylate and 300 ml of methyl isobutyl ketone were charged. Acatalytic amount of 2,2′-azobis(methyl 2-methylpropionate) was addedthereto as a radical polymerization initiator, and polymerization wasallowed to proceed at 80° C. for 6 hours in a nitrogen stream. Thereaction solution was cooled and then poured in a large amount ofheptane to precipitate a polymer. The crystal was collected byfiltration and dissolved in diethylene glycol dimethyl ether, andheptane and methyl isobutyl ketone contained in the solution wereremoved by distillation under reduced pressure to obtain Polymer A2-6(glycidyl methacrylate/1-ethoxyethyl methacrylate/2-hydroxyethylmethacrylate/benzyl methacrylate) as a diethylene glycol dimethyl ethersolution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 8,000 andthe molecular weight distribution (Mw/Mn) was 1.7.

Synthesis Example 14 Synthesis of A2-7

Into a 500 ml-volume three-neck flask, 51.2 g (0.36 mol) of glycidylmethacrylate, 21.1 g (0.12 mol) of benzyl methacrylate, 10.3 g (0.12mol) of methacrylic acid and 300 ml of methyl isobutyl ketone werecharged. A catalytic amount of 2,2′-azobis(methyl 2-methylpropionate)was added thereto as a radical polymerization initiator, andpolymerization was allowed to proceed at 80° C. for 6 hours in anitrogen stream. The reaction solution was cooled and then poured in alarge amount of heptane to precipitate a polymer. The crystal wascollected by filtration and dissolved in diethylene glycol dimethylether, and heptane and methyl isobutyl ketone contained in the solutionwere removed by distillation under reduced pressure to obtain PolymerA2-7 (glycidyl methacrylate/benzyl methacrylate/methacrylic acid) as adiethylene glycol dimethyl ether solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 4,000 andthe molecular weight distribution (Mw/Mn) was 1.6.

Comparative Synthesis Example 1 Synthesis of A′1-8

Into a 500 ml-volume three-neck flask, 51.2 g (0.36 mol) of tert-butylmethacrylate, 21.1 g (0.12 mol) of benzyl methacrylate, 10.3 g (0.12mol) of methacrylic acid and 300 ml of methyl isobutyl ketone werecharged. A catalytic amount of 2,2′-azobis(methyl 2-methylpropionate)was added thereto as a radical polymerization initiator, andpolymerization was allowed to proceed at 80° C. for 6 hours in anitrogen stream. The reaction solution was cooled and then poured in alarge amount of heptane to precipitate a polymer. The crystal wascollected by filtration and dissolved in propylene glycol monomethylether acetate, and heptane and methyl isobutyl ketone contained in thesolution were removed by distillation under reduced pressure to obtainPolymer A′1-8 (tert-butyl methacrylate/benzyl methacrylate/methacrylicacid) as a propylene glycol monomethyl ether acetate solution.

As for the molecular weight and molecular weight distribution of thepolymer obtained, GPC measurement using polystyrene as the standardrevealed that the weight average molecular weight was about 8,000 andthe molecular weight distribution (Mw/Mn) was 1.6.

Comparative Synthesis Example 2 Synthesis of A′1-9

Into a 500 ml-volume three-neck flask, 72.1 g of poly-4-hydroxystyrene(VP-8000, produced by Nippon Soda Co., Ltd.), 16.4 g of ethyl vinylether and 300 ml of ethyl acetate were charged. A catalytic amount ofpara-toluenesulfonic acid was added thereto, and reaction was allowed toproceed at room temperature for 3 hours in a nitrogen stream. Afteradding a small amount of triethylamine, the mixture was washed with purewater. Propylene glycol monomethyl ether acetate was added to the ethylacetate layer, and ethyl acetate was removed by distillation underreduced pressure to obtain Polymer A′1-9(p-1-ethoxyethoxystyrene/p-hydroxystyrene) as a propylene glycolmonomethyl ether acetate solution.

In the polymer obtained, from NMR measurement, the constituent ratiobetween p-1-ethoxyethoxystyrene unit and p-hydroxystyrene unit was about35:65. Also, GPC measurement using polystyrene as the standard revealedthat the weight average molecular weight was about 9,000 and themolecular weight distribution (Mw/Mn) was 1.2.

Comparative Synthesis Example 3 Synthesis of A′-10

Synthesis of A′-10 was performed in accordance with Synthesis Example 1of JP-A-2004-264623.

Into a three-neck flask, 7 parts by mass of2,2′-azobis(2,4-dimethylvaleronitrile) and 200 parts by mass ofdiethylene glycol ethyl methyl ether were charged and subsequently, 40parts by mass of 1-(cyclohexyloxy)ethyl methacrylate, 5 parts by mass ofstyrene, 45 parts by mass of glycidyl methacrylate, 10 parts by mass of2-hydroxyethyl methacrylate and 3 parts by mass of α-methylstyrene dimerwere charged. After nitrogen substitution, stirring was gently started.The temperature of the solution was raised to 70° C., and thistemperature was kept for 5 hours to obtain a polymer solution containingCopolymer (A′-10).

As for the molecular weight of the polymer obtained, GPC measurementusing polystyrene as the standard revealed that the weight averagemolecular weight was about 11,000 and the molecular weight distribution(Mw/Mn) was 1.9.

Examples 1 to 9 and Comparative Examples 1 to 6 (1) Preparation ofPositive Photosensitive Resin Composition Solution

A uniform solution was obtained by mixing the components shown in Table1 below and then filtered using a polytetrafluoroethylene-made filterhaving a pore size of 0.2 μm to prepare a positive photosensitive resincomposition solution.

(2) Evaluation of Storage Stability

The viscosity at 23° C. of the positive photosensitive resin compositionsolution was measured using an E-type viscometer manufactured by ToldSangyo Co., Ltd. Also, the viscosity of the composition after storage ina constant temperature bath at 23° C. for one month was measured. Thestorage stability was rated A when the increase of viscosity afterstorage at room temperature for one month based on the viscosity afterthe preparation was less than 5%, and rated B when 5% or more. Theresults are shown in Table 2 below.

(3) Evaluation of Sensitivity and Residual Film Ratio at Development

The positive photosensitive resin composition solution was applied on asilicon wafer having thereon a silicon oxide film by spin-coating andthen pre-baked on a hot plate at 100° C. for 60 seconds to form a 3μm-thick coating film.

The coating film was then exposed through a predetermined mask by usingan i-line stepper (FPA-3000i5+, manufactured by Canon Inc.), baked at50° C. for 60 seconds, developed with the alkali developer shown inTable 2 (an aqueous 2.38 mass % or 0.4 mass % tetramethylammoniumhydroxide solution) at 23° C. for 60 seconds and then rinsed withultrapure water for 1 minute. The optimal exposure dose (Eopt) whenresolving a 5-μm line-and-space at 1:1 by these operations was taken asthe sensitivity.

The film thickness of the unexposed area after development was measured,and the ratio to the film thickness after coating (film thickness ofunexposed area after development÷ film thickness after coating×100(%))was determined, whereby the residual film ratio at the development wasevaluated.

The evaluation results of sensitivity and residual film ratio atdevelopment are shown in Table 2.

(4) Evaluation of Heat Resistance, Transmittance and Adhesion

A coating film was formed in the same manner as in (3) above except thatin (3) above, a transparent substrate (Corning 1737, produced by CorningInc.) was used in place of the silicon wafer having thereon a siliconoxide film. The coating film was exposed to an ultraviolet ray at 365 nmand a light intensity of 18 mW/cm² by using a proximity exposure device(UX-1000SM, manufactured by Ushio Inc.) while tightly contacting apredetermined mask with the coating film, then developed with an alkalideveloper (an aqueous 2.38 mass % tetramethylammonium hydroxidesolution) at 23° C. for 60 seconds, and rinsed with ultrapure water for1 minute. By these operations, a pattern of 10-μm line-and-space at 1:1was formed. The obtained pattern was further subjected to entire surfaceexposure for 100 seconds and then heated in an oven at 220° C. for 1hour to form a heat-cured film on a glass substrate. Also, the patternafter the above-described entire surface exposure for 100 seconds washeated in an oven at 240° C. for 1 hour, whereby a heat-cured film wassimilarly formed on a glass substrate.

The heat resistance was evaluated by measuring the rate of change in thebottom dimension between before and after heat curing (1−bottomdimension of heat-cured film÷bottom dimension after development)×100(%).The heat resistance was rated A when the rate of change was less than5%, and rated B when 5% or more.

The transmittance of the heat-cured film obtained by the heating at 220°C. for 1 hour was measured by a spectrophotometer (U-3000, manufacturedby Hitachi, Ltd.) in the wavelength range of 400 to 800 nm. Thetransmittance was rated A when the minimum transmittance exceeded 95%,rated B when from 90 to 95%, and rated C when less than 90%.

On the other hand, the transmittance of the heat-cured film obtained bythe heating at 240° C. for 1 hour was measured by a spectrophotometer(U-3000, manufactured by Hitachi, Ltd.) in the wavelength range of 400to 800 nm, and the minimum transmittance was determined. Furthermore,the film thickness was measured using DEKTAK-3 manufactured by ULVAC,and the transmittance per film thickness of 1 μm was determined.

The heat-cured film obtained by the heating at 220° C. for 1 hour wasincised vertically and horizontally by a cutter at intervals of 1 mm,and a tape peeling test was performed using Scotch Tape. The adhesionbetween the cured film and the substrate was evaluated from the area ofthe cured film transferred to the back surface of the tape. The adhesionwas rated A when the area was less than 1%, rated B when from 1 to lessthan 5%, and rated C when 5% or more.

The evaluation results of heat resistance, transmittance and adhesionare shown in Table 2.

TABLE 1 Component (A) Component (B) Component (C) Basic Compound SolventBlending Parts Parts Parts Parts Parts Kind Kind Ratio of by by by by by(A1) (A2) Resins (A1:A2) mass Kind mass Kind mass Kind mass Kind massSurfactant Example 1 A1-1 A2-1 50:50 100 B1 3.0 C1 2.1 D1 0.02 E1 160 F10.05 Example 2 A1-2 A2-2 50:50 100 B2 2.8 C2 2.1 D2 0.02 E2 160 F1 0.05Example 3 A1-3 A2-3 50:50 100 B3 2.5 C3 2.1 D1 0.02 E3 160 F2 0.05Example 4 A1-4 A2-4 50:50 100 B4 2.5 C1 2.1 D2 0.02 E1 160 F2 0.05Example 5 A1-5 A2-5 50:50 100 B1 + B4 B1: 1.3 + C1 2.1 D1 0.02 E2 120 F30.05 B4: 1.3 Example 6 A1-6 A2-6 50:50 100 B1 2.8 C1 2.1 D1 0.02 E3 120F3 0.05 Example 7 A1-7 A2-7 50:50 100 B1 3.0 C1 2.1 D1 0.02 E1 + E3 E1:80 + F1 0.05 E3: 80 Example 8 A1-1 A2-6 60:40 100 B2 3.0 C1 2.1 D1 0.02E1 160 F1 0.05 Example 9 A1-3 A2-5 30:70 100 B2 3.0 — — D1 0.02 E3 160F1 0.05 Comparative A1-1 — 100:0  100 B1 3.0 C1 2.1 D1 0.02 E1 120 F10.05 Example 1 Comparative — A2-1  0:100 100 B1 3.0 C1 2.1 D1 0.02 E1120 F1 0.05 Example 2 Comparative  A′1-8 A2-1 50:50 100 B1 3.0 C1 2.1 D10.02 E1 120 F1 0.05 Example 3 Comparative  A′1-9 — 100:0  100 B1 3.0 C12.1 D1 0.02 E1 120 F1 0.05 Example 4 Comparative A′-10 — 100  B′6 10.0 — — — — E3 257 — — Example 5 Comparative A′-10 — 100  B′6 5.0 — — — — E3245 — — Example 6

The components (A), (B) and (C), basic compounds and solvents shown inTable 1 are as follows.

Component (A):

The numerical value on the right side of the constituent unit indicatesthe molar ratio of the constituent unit.

Component (B):

B1: IRGACURE PAG 103 (produced by Ciba Specialty Chemicals Corp.)

B2: IRGACURE PAG 108 (produced by Ciba Specialty Chemicals Corp.)

B3: CGI 1380 (produced by Ciba Specialty Chemicals Corp.)

B4: IRGACURE PAG 121 (produced by Ciba Specialty Chemicals Corp.)

B5: CGI 725 (produced by Ciba Specialty Chemicals Corp.)

B′6: 4,7-di-n-butoxy-1-naphthyltetrahydrothiopheniumtrifluoromethanesulfonate

Component (C):

C1: γ-glycidoxypropyltrimethoxysilaneC2: β-(3,4-epoxycyclohexyl)ethyltrimethoxysilaneC3: γ-methacryloxypropyltrimethoxysilane

[Basic Compound]

D1: 4-dimethylaminopyridineD2: 1,5-diazabicyclo[4,3,0]-5-nonene

[Solvent]

E1: propylene glycol monomethyl ether acetateE2: diethylene glycol dimethyl etherE3: diethylene glycol ethyl methyl ether

[Surfactant]

F1: Florad F-430 (produced by Sumitomo 3M, Ltd.)F2: Megaface R-08 (produced by Dainippon Ink and Chemicals, Inc.)F3: PolyFox PF-6320 (produced by OMNOVA)

TABLE 2 Transmittance Transmittance Concentration of Storage Sensitivity(Eopt) Residual Film Heat (after heating at (after heating at Developer(mass %) Stability (mJ/cm²) Ratio (%) Resistance Adhesion 220° C. for 1hour) 240° C. for 1 hour) Example 1 2.38 A 48 99 A A A 98% Example 22.38 A 49 99 A A A 96% Example 3 2.38 A 52 98 A A A 97% Example 4 2.38 A51 98 A A A 96% Example 5 2.38 A 52 99 A A A 98% Example 6 2.38 A 50 99A A A 96% Example 7 2.38 A 52 99 A A A 97% Example 8 0.4 A 55 99 A A A98% Example 9 0.4 A 57 99 A A A 98% Comparative 2.38 A 49 98 B A A 98%Example 1 Comparative 2.38 A Image was not formed. A A 98% Example 2Comparative 2.38 A Image was not formed. A A 97% Example 3 Comparative2.38 A 51 97 B A B 70% Example 4 Comparative 2.38 A >800 99 A C A 85%Example 5 Comparative 0.4 A >800 99 A C A 86% Example 6

As apparent from Table 2, the positive photosensitive resin compositionof the present invention is excellent in the sensitivity, residual filmratio and storage stability and when cured, can form a cured filmexcellent in the heat resistance, adhesion, transmittance and the like.

The positive photosensitive resin composition of the present inventionis assured of high sensitivity, so that a liquid crystal display device,an integrated circuit device, a solid-state imaging device or an organicEL device can be efficiently produced.

A liquid crystal display device obtained using the positivephotosensitive resin composition of the present invention is high in thetransmittance and can reduce the power consumption.

INDUSTRIAL APPLICABILITY

The positive photosensitive resin composition of the present inventionensures that a coating film excellent in the sensitivity, residual filmratio and storage stability is obtained and when cured, a cured filmexcellent in the heat resistance, adhesion, transmittance and the likeis obtained. The pattern forming method of the present invention issuitably used for the formation of a flattening film, a protective filmor an interlayer insulating film of electronic components such as liquidcrystal display device, integrated circuit device, solid-state imagingdevice and organic EL.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

This application is based on Japanese Patent Application (PatentApplication No. 2007-256203) filed on Sep. 28, 2007 and Japanese PatentApplication (Patent Application No. 2008-246883) filed on Sep. 25, 2008,the contents of which are incorporated herein by way of reference.

1. A positive photosensitive resin composition comprising: (A1) a resincontaining a constituent unit represented by the following formula (1)having an acid-dissociable group, the resin being alkali-insoluble orsparingly alkali-soluble and becoming alkali-soluble when saidacid-dissociable group dissociates; (A2) a resin containing aconstituent unit having a functional group capable of reacting with acarboxyl group to form a covalent bond; and (B) a compound capable ofgenerating an acid upon irradiation with an actinic ray or radiation:

wherein R¹ represents a hydrogen atom, a methyl group, a halogen atom ora cyano group, each of R² and R³ independently represents a hydrogenatom, a linear or branched alkyl group, or a cycloalkyl group, providedthat at least one of R² and R³ represents a linear or branched alkylgroup or a cycloalkyl group, R⁴ represents a linear or branched alkylgroup which may be substituted, a cycloalkyl group which may besubstituted, or an aralkyl group which may be substituted, and R² or R³may combine with R⁴ to form a cyclic ether.
 2. The positivephotosensitive resin composition as claimed in claim 1, wherein thecomponent (B) is a compound capable of generating an acid uponirradiation with an actinic ray at a wavelength of 300 nm or more. 3.The positive photosensitive resin composition as claimed in claim 1,wherein the component (B) is a compound containing an oxime sulfonategroup represented by the following formula (2):

wherein R⁵ represents a linear or branched alkyl group which may besubstituted, a cycloalkyl group which may be substituted, or an arylgroup which may be substituted.
 4. The positive photosensitive resincomposition as claimed in claim 3, wherein the component (B) is acompound represented by the following formula (3):

wherein R⁵ is the same as R⁵ in formula (2), X represents a linear orbranched alkyl group, an alkoxy group or a halogen atom, m represents aninteger of 0 to 3, and when m is 2 or 3, each X may be the same as ordifferent from every other X.
 5. The positive photosensitive resincomposition as claimed in claim 1, further comprising: (C) an adhesionaid.
 6. The positive photosensitive resin composition as claimed inclaim 1, wherein the component (A2) contains a constituent unit having afunctional group capable of reacting with a carboxyl group to form acovalent bond and a constituent unit represented by formula (1).
 7. Acured film forming method comprising: a step of applying the positivephotosensitive resin composition claimed in claim 1 on a substrate anddrying it to form a coating film; a step of exposing the coating film toan actinic ray or radiation through a mask; a step of developing theexposed film with an alkali developer to form a pattern; and a step ofheat-treating the obtained pattern.
 8. The cured film forming method asclaimed in claim 7, further comprising: a step of exposing the entiresurface of the film, after the step of developing the coating film withan alkali developer to form a pattern but before the step ofheat-treating the obtained pattern.
 9. A cured film formed by using thecured film forming method claimed in claim
 7. 10. A liquid crystaldisplay device having the cured film claimed in claim
 9. 11. Anintegrated circuit device having the cured film claimed in claim
 9. 12.A solid-state imaging device having the cured film claimed in claim 9.13. An organic EL device having the cured film claimed in claim
 9. 14.The positive photosensitive resin composition as claimed in claim 1,wherein the functional group capable of reacting with a carboxyl groupto form a covalent bond of the component (A2) is an epoxy group.
 15. Thepositive photosensitive resin composition as claimed in claim 1, whereinthe component (A2) is synthesized by using a radical polymerizablemonomer represented by the following formula (3):

wherein X represents a divalent linking group, R⁷ represents a hydrogenatom, a methyl group or a halogen atom, each of R⁸, R⁹ and R¹⁰independently represents a hydrogen atom or an alkyl group, and n is aninteger of 1 to
 10. 16. The positive photosensitive resin composition asclaimed in claim 1, wherein the component (A2) is synthesized by using aradical polymerizable monomer represented by the following formula (4):

wherein X represents a divalent linking group, R⁷ represents a hydrogenatom, a methyl group or a halogen atom, each of R¹¹ and R¹²independently represents a hydrogen atom or an alkyl group, and n is aninteger of 1 to
 10. 17. The positive photosensitive resin composition asclaimed in claim 1, wherein the component (A2) is synthesized by using aradical polymerizable monomer represented by the following formula (5):

wherein X represents a divalent linking group, R⁷ represents a hydrogenatom, a methyl group or a halogen atom, each of R¹³, R¹⁴ and R¹⁵independently represents a hydrogen atom or an alkyl group, and n is aninteger of 1 to
 10. 18. The positive photosensitive resin composition asclaimed in claim 16, wherein the radical polymerizable monomerrepresented by formula (4) is 3,4-epoxycyclohexylmethyl acrylate or3,4-epoxycyclohexylmethyl methacrylate.
 19. The positive photosensitiveresin composition as claimed in claim 1, wherein the functional groupcapable of reacting with a carboxyl group to form a covalent bond of thecomponent (A2) is an oxetane group.